Automatic gripping device for stepladders



June 16, 1942. H. J. MYERS 2,286,923

. AUTOMATIC GRIPPING DEVICE FOR STEPLADDERS Filed Sept. 23, 1941 2 Sheets-Shet 1 mforei ags/m- Inc/own;

June 16, 1942.

H. J. MYERS 2,286,923

AUTOMATIC GRIPPING DEVICE FOR STEPLADDERS Filed Sept. 23, 1941 2 Sheets-Sheet 2 auzze lflll llll i4 .24 i II I35 ii izii' v a Q) mfordJM ars Patented June 16, 1942 warren stares AUTOMATIC GRHPIN G DEVICE FOR STEPLAIDDERS This invention relates to step ladders of that general class shown and described in my prior United States patent, No. 1,982,172, the present invention .being an improvement thereon.

The object of the invention is to simplify the construction of the step ladder thereby to reduce the cost of manufacture and at the same time render the ladder more durable and efficient in operation.

A further object of the invention is to provide a step ladder which may be adjusted to rest on an uneven surface and further to provide an automatic gripping device for clamping the parts in a selected position of adjustment.

A further object is to provide a step ladder, the rear supporting legs of which are automatically locked against accidental displacement when said ladder is subjected'to the weight of a person using the same.

A further object is to provide an automatic leg gripping device comprising coacting spring-= pressed brackets pivotally mounted on the front legs of the ladder near the top thereof and pivotally connected with a substantially V-shaped brace carried by the rear supporting legs so that, when a person steps on the ladder, his or her weight will cause the converging members of the brace to frictionally engage the rear legs of the ladder and effectually prevent accidental separation or displacement of said rear legs.

A further object is to provide a novel form of folding spreader for the ladder said spreader being swiveled to the front and rear legs of said ladder so as to permit independent vertical adjustment of said rear legs.

Further objects and advantages will appear in the following description. 1

In the accompanying drawings forming a part of this specification and in which similar numerals of reference indicate corresponding parts in all the figures of the drawings:

Figure 1 is a rear elevation of a folding step ladder provided with an automatic leg gripping device constructed in accordance with the present invention,

Figure 2 is a side elevation showing in dotted lines the position of the parts when the gripping device is actuated under the influence of the weight of a personstanding on the. ladder,

Figure 3 is a rear elevation on a reduced scale showing how the rear legs may be adjusted to accommodate the ladder to uneven surfaces,

Figure 4 is a transverse sectional View taken on the line '--4 of Figure 2,

1 of a substantially V-shaped rear brace 29.

Figure 5 is a detail transverse sectional view taken on the line 55 of Figure 6, and

' Figure 6 is a vertical sectional view taken on the line 66 of Figurel.

The ladder comprises back legs 5 and front legs 6 and a top or platform I of any approved design secured to the front legs'by angle bars 8. The opposed surfaces of the front legs 6 are recessed at stated intervals and steps 9 have their ends seated in said recesses and secured therein by bolts or rods l0 disposed below the respective steps with their ends inserted through the legs and fitted with washers II and nuts 12 whereby the legs will be caused to clamp the steps and firmly secure the same.

Pivotally mounted at l3 on the inner faces of the legs 6 in suitable spaced relation to the platform I are brackets l4 rigidly united by a connecting bar I5 so as to cause the brackets to move in unison.

' Pivotally connected at 16 with the rear legs 5 is a cross bar I! and secured to the center of said cross bar is a yoke l8, in the upper end of which is pivotally mounted, at IS, the small end The rear brace 26 is preferably formed of channel iron and the diverging ends of the side members of the brace 28) are pivotallyunited at 2| with the free or projecting ends of the brackets [4 so that, when a downward pressure is exerted on the forward legs 6 of the ladder, the V-shaped brace 21! will be actuated to firmly grip the upper portions of the rear legs 5. 'The upper portions of the rear legs 5 extend in front of the brace 20 and are normally spaced slightly therefrom with their upper or free ends resting on the connecting bar l5, as best shown in Figure 6 of the drawings. Extending laterally from the connecting bar l5 are spaced pairs of guide pins 22, one pin of each pair being disposed at the opposite sides of each rear leg 5 so as to form guides for said rear legs. The material at the outer ends of the pivoted brackets i4 is bent inwardly to form stop lips 23 which bear against the adjacent side members of the V-shaped brace 20, as best shown in Figure 5 of the drawings.

Extending around the pivot bolts l3 of the brackets M are coiled springs 24, one end of each spring being anchored by a staple 25 to the inner face of the adjacent front leg 6 while the other end thereof rests on the connecting bar l5, said springs serving normally and yieldably to hold the brackets M in a horizontal position with the inner faces of the V-shaped brace 20 spaced from the rear legs of the ladder so as to permit either of said rear legs to be adjusted vertically to permit the ladder to be supported on an uneven surface, as best shown in Figure 3 of the drawings.

The front and rear ends of the ladder are connected by a spreader 26 preferably formed in two sections having their inner ends pivotally united at 21. The forward section of the spreader is of V shape construction and is pivotally connected at 28 to a bolt 29 swiveled in a bracket 30 secured to the lower face of one of the ladder steps 9. The rear section of the spreader 26 has a swiveled connection 3| with bolts 32 extending through the cross bar I! so as to permit the spreader to tilt laterally when adjusting the rear legs of the ladder vertically and thus prevent binding or wedging action between the parts. The forward portion of the rear section of the spreader forms a loop or handle 33 by means of which the spreader sections may be moved to a horizontal position when the ladder is set up for use.

Extending transversely of the V-shaped brace 20 is a rod 34 which receives suitable staples 35 secured to a pivoted rest or platform 36. The platform 36 is substantally triangular in shape, as shown, so as to fit within the confines of the V-shaped brace 20 when not in use, said platform being adapted to be swung upwardly with its small end beneath the adjacent step 9 when the ladder is in use so as to permit the rear portion of the platform to be used as a support for a bucket or other article.

In using the ladder, the front and rear legs thereof are moved to open position and the spreader moved to extended position by pressing downwardly on the operating handle 33, after which the platform 36 is swung upwardly to a horizontal position, as best shown in Figure 2 of the drawings. With the parts of the ladder in this position, the springs 24 will hold the brackets M in a horizontal plane with the side members of the Vshaped brace 20 spaced from the rear legs of the ladder. Either rear leg of the ladder may now be adjusted vertically to permit the ladder to be supported on an uneven surface by merely shoving upwardly on the rear leg to be adjusted. By now stepping on the ladder, the weight of the person will tilt the brackets l4 upwardly against the tension of the springs 24 and in doing so will cause the V- shaped brace 29 to frictionally engage the adjacent portions of the rear legs of the ladder and thereby hold the legs of the ladder in a set position as long as a person is standing on the ladder. When the weight of a person is removed from the steps of the ladder, the springs 24 will automatically return the brackets M to lowered or horizontal position and in doing so will move the V-shaped brace 20 out of engagement with the rear legs of the ladder so as to permit any further vertical adjustment of either rear leg if necessary. By pulling upwardly on the handle 33, the spreader sections will be moved upwardly thus permitting the rear legs of the ladder to be folded fiat against the forward legs thereof so as to take up very little room.

It will be noted that the cross bar I! in conjunction with the rear member 23 forms a substantially triangular brace that reinforces the back legs of the ladder in two directions. It will also be noted that the cross bar and spreader are disposed below the steps and out of the way of a scaffolding board when the ladder is used for supporting such scaffolding boards.

When the device is used on ten or twelve foot ladders, the same construction of V-shaped brace will be employed but said brace will be operatively connected with the ladder in spaced relation to the top thereof so as to permit the use of shorter rear legs and said rear legs will be provided with an additional cross brace arranged below the pivoted cross brace and to which the spreader will be attached so as to permit the spreader to be easily reached by the user.

From the foregoing description it is thought that the construction and operation of the device will be readily understood by those skilled in the art and further description thereof is deemed unnecessary.

While I have shown and described my improved automatic gripping device applied to a small step ladder, it will, of course, be understood that said gripping device may be used in connection with any size or style of ladder without departing from the spirit of the invention.

Having thus described the invention, what is claimed as new is:

1. A step ladder comprising front and rear legs, a cross bar pivotally connected with the rear legs, spring-pressed brackets pivotally mounted on the front legs, and means carried by the cross bar and pivotally connected with the brackets for gripping the rear legs when weight is applied to the ladder and actuated to automatically release said gripping means when the weight is removed from said ladder.

2. A step ladder comprising front and rear legs, spring-pressed brackets pivotally mounted on said front legs, a cross bar pivotally connected with the rear legs, and a brace pivotally connected with the cross bar and said brackets whereby the weight of a person on the ladder will tilt the brackets against the tension of the springs thereby to cause the brace to grip the rear legs and prevent accidental movement thereof.

3. A step ladder comprising front and rear legs, brackets pivotally mounted for tilting movement on the front legs, rear legs movable vertically with respect to the front legs, a cross bar pivotally connected with the rear legs, a brace normally spaced from said rear legs and forming a pivotal connection between the cross bar and said brackets, and springs operatively connected with the brackets whereby the weight of a person on the ladder will tilt the brackets against the tension of the springs to cause the brace to grip said rear legs and prevent accidental movement thereof.

4. A step ladder comprising front and rear legs, the front legs being provided with steps, springpressed brackets pivotally mounted on the front legs, a bar connecting said brackets, the upper ends of the rear legs resting on said bar, a cross bar pivotally connected with the rear legs, a substantially V-shaped brace having its lower end pivotally connected with the cross bar and its upper end pivotally connected with the brackets, and a substantially triangular shaped platform pivotally mounted within the V-shaped brace and having one end thereof movable to operative position beneath one of the steps of the front legs.

5. A step ladder comprising front and rear legs, brackets mounted for tilting movement on the front legs and having their outer ends provided with inwardly extending lips, a connect ing bar uniting said brackets and provided with spaced guide pins adapted to receive the upper ends of the rear legs between them, a cross bar pivotally connected with said rear legs, a substantially V-shaped brace pivotally connected with the cross bar and with the brackets at said inwardly extending lips, the side members of the V-shaped brace being normally spaced from the rear legs, and spring each having one end thereof anchored to the front legs and its intermediate portion coiled around the pivot point of the adjacent bracket with its free end resting on the connecting bar whereby the weight of a person on the ladder will tilt the brackets against the tension of the springs and cause the V- shaped brace to grip said rear legs.

6. A step ladder including front and rear legs, a cross bar forming a pivotal connection between said rear legs, a spreader including pivotally united front and rear sections, one of which is swiveled to the front legs and the other to the rear legs, brackets pivotally mounted for tilting movement on the front legs near the upper portions thereof and having their free ends projected laterally beyond the rear edges of said front legs, a yoke secured to the cross bar, a substantially V-shaped brace pivotally mounted in the yoke and having its legs pivotally connected with the projecting ends of the brackets, and springs operatively connected with the pivoted ends of the brackets for normally holding the V-shaped brace out of engagement with the rear legs and causing said brace to automatically grip said rear legs when the ladder is subjected to the weight of a person using the same.

7 A step ladder comprising front and rear legs, a cross bar forming a pivotal connection between the rear legs to permit vertical adjustment thereof, brackets pivotally mounted on the front legs, a bar connecting said brackets and against which the upper end of the rear legs normally rest, guide pins extending laterally from the bar on opposite sides of the rear legs, a yoke secured to the intermediate portion of the cross bar, a substantially V-shaped brace pivotally mounted in the yoke and having its upper ends pivotally connected with the adjacent brackets, lips projecting inwardly from said brackets at their pivotal connection with the brace, and springs operatively connected with the pivot pins of the brackets and each having one end thereof anchored to the adjacent front legs and its other end resting on the connecting bar of the brackets.

8. A step ladder comprising front and rear legs, one of which is provided with steps, springpressed brackets pivotally mounted on the front legs adjacent the top of the ladder, a cross bar pivotally connected with the rear legs, a yoke secured to the lower face of one of the steps, a bolt swiveled in said yoke, a spreader connecting the front and rear legs and formed with pivotally connected sections, one of which is tapered and pivotally connected with the swiveled bolt, the other section being pivotally connected with the cross bar, and means carried by the cross bar and pivotally connected with the brackets for gripping the rear legs when the weight of a person is applied to the ladder and actuated to automatically release said means when the weight of a person is removed.

9. A step ladder including front and rear legs, depressible means mounted on the front legs, and means carried by the rear legs and operatively connected to said depressible means for automatically gripping the rear legs when weight is applied to the front legs and actuated to release the grip on said rear legs when the weight is removed.

10. A step ladder including coacting stationary and movable legs, means for gripping the movable legs and holding the same in adjusted position, and actuating means for the gripping means responsive to the weight of a person upon th stationary legs for automatically effecting gripping of the movable legs when subjected to said weight and actuated to release the gripping means when the weight is removed therefrom.

11. A step ladder including coacting stationary and movable legs, means for gripping the movable legs and holding the same in adjusted position, and actuating means for the gripping means carried by certain of the legs and responsive to the weight of a person for automatically effecting gripping of the movable legs when subjected to said weight.

HANSFORD J. MYERS. 

